Telephone system



1937. w. w. CARPENTER ET AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet l .W. w. CARPENTERSf'A. E. HAGUE AT TOR/VEV Aug. 10, 1937. w. w. CARPENTER ET AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1956 8 Sheets-Sheet 2 /NVENTOR$,W l4.CARPENTER 'A.E. HAGUE 51/ ATTORNEY Aug. 10, 1937- w. w. CARPENTER ET AL2,089,338

TELEPHONE SYSTEM Filed March 11, 1956 8 Sheets-Sheet 5 INVENTORSZW. W.CARPENTER By AE. HAGUE AT TORNEV 1937- w. w. CARPENTER El AL 2,089,338-

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 4 EADER FULL 4.90F/G4 FULL MECH JUNCTOR "8"JUNC7'0R PM .w. m CARPENTER 351 ,5. HAGUEATTORNEY Aug. 10, 1937.

w. w. CARPENTER El AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 5 U, y n I ATTORNEYAug. 10, 1937.

w. w. CARPENTER ET AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 6 .W. W. CARPENTERgfnf. HAGUE ATTOPNEV Aug. 10, 1937. w. w. CARPENTER ET AL 2,089,338

' TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 7 INVENTOAZ: 5HAGUE ii o a. 20 unnecessary duplication of equipment.

Patented Aug. 10, 1937 UNITED STATES PATENT OFFICE TELEPHONE SYSTEMApplication March 11, 1936, Serial No. 68,263

10 Claims.

oifice, registering devices are employed which are associated with theincoming trunk circuit. In the case of trunk circuits incoming from dialoffices, the registering devices are positioned by means of revertiveimpulses under the control of the originating sender. In the case oftrunk circuits incoming from manual ofiices, the registering device isalso associated with an operators position and receives its settingunder the control of the operator.

Heretofore, separate switching arrangements have been employed inconnecting dial and manual trunk circuits with their respectiveregistering devices. If either group of registering devices is small,this separation requires an In accordance with the present invention, aunitary switching device is provided for connecting the trunk circuitsand registering devices together with means for permitting connectionsbetween corresponding equipment only.

.More specifically, the switching device comprises primary and secondarycross-bar switches with interconnecting links in which primary contactsand links are individual to the trunk types W and secondary contacts areindividual to register types, the links having access to both registertypes. Means is provided to record the type of trunk seizing theswitching device and responsive to this record, only the correspondingtype of register may be tested and connected with.

The present disclosure forms a part of the complete system disclosed inthe application of W. W. Carpenter, Serial No. 68,262, filed March 11,1936.

The invention will be more clearly understood from a consideration ofthe following description in association with the drawings in which:

Fig. 1 shows the sender group testing and link lock-out relays;

Fig. 2 shows a number of control relays;

Figs. 3 and 6 show the multicontact connecting relays;

Fig. 4 shows a part of the sender link switches;

Fig. 5 shows the junctor group and selecting relays;

Fig. '7 shows the sender selecting relays;

Fig. 8 is a skeleton showing of the sender connector; and

Fig. 9 shows the manner in which Figs. 1 to 7 are to be arranged. 1Referring first to Fig. 8, the sender connector consists of threeprimary cross-bar switches and three secondary cross-bar switches. Thejunctors are connected to contacts appearing in the horizontals of theprimary switches; the senders are connected to the horizontals of thesecondary switches; while the links connect verticals of the primaryswitches to verticals of the secondary switches. The primary switchesare split vertically to divide the links into groups of three, and tenjunctors are connected to the horizontals served by each group of threelinks, being multipled between switches where necessary. Therefore theprimary switches provide thirty links for serving one hundred junctors.The three links of one group are connected one to each of the threesecondary switches, thereby giving each incoming junctor access to allof the thirty senders. As will be pointed out in the description of thecircuits, assuming that certain groups of junctors, for example groups 1to H], are incoming from manual ofiices, they will be served only by theB senders. Such junctors are grouped by themselves and are thereforeserved by links individual to that purpose. However, the links havephysical access to all senders sothat regrouping of the junctors maytake place without rewiring the switches themselves. It is, of course,to be understood that the grouping shown is merely illustrative.

Detailed description This link control circuit, like the line group andcontrol circuit described in the application of W. W. Carpenter,above-identified, is arranged to act as an emergency control circuit foran adjacent or mate frame. The dotted rectangle 350 of Fig. 3 has beenused as a convenient means of indicating the relationship between thetwo control circuits and all conductors entering the rectangle areconsidered to emerge at the mate frame.

Test for presence of idle link and sender Turning now to Figs. 1 to '7,when a full mechanical junctor has been seized, it grounds conductor 42!completing a circuit over the inner back contact individual to thatjunctor on relay 62L back contact of primary hold magnet 425, conductor426, outer back contact of relay 109, conductor I30, outer right backcontact of relay 62L contact of jack 647 to the winding of group relay622 and battery. The circuit of relay 622, which is individual to thegroup of ten junctors including the calling junctor, also extends inparallel over the back contacts of the hold magleft back contact ofrelay 228.

nets individual to the other two sender links which serve this group ofjunctors and over the back contacts of the corresponding sender groupbusy relays. Relay 52! is operated if the control circuit is busy, holdmagnet 425 is operated if the corresponding sender link is in use withanother junctor and relay l'99 is operated if all of the fullmechanicalsenders in the corresponding group are busy. Therefore, relay 622 canonly operate if the control circuit is idle and an idle link to an idlesender is available.

Connecting junctor group to control circuit Assuming that relay 922operates, at its inner right contact, it closes a holding ground foritself over the contacts of magnet 425, relay 199 and relay 62L It alsoconnects ground over its outer right contact, conductor 64!, and theright back contact of relay 546 to the winding of relay 552 and battery,to start the control circuit functioning. With relay 552 operated, acircuit is closed from battery through the winding of relay542, throughrectangle 959, over the right back contact of relay 559 or the innerright back contact of relay 543 of the mate control circuit, indicatingthat the mate control circuit is functioning, back through rectangle359, inner left back contact of relay 559 and the outer left backcontact of relay 543 of the home control circuit to ground at the leftfront contact of relay 552. Relay 542 in turn closes circuits frombattery through the windings of relays 399 and 699, over its leftcontacts in parallel, over the left back contact of relay 545, conductor554 to ground at the inner Relays 399 and 599 connect the junctor groupcircuits and the sender group circuits to the home control circuit.Relay 542 also opens the circuit of relay 545 to prevent interferencefrom the mate frame until the control circuit has completed itsfunction. It also connects ground over the outermost front contact ofrelay 599 to conductor 554 to hold relays 699 and 399 operated.

Choosing jnnctor group to be served With relay 699 operated, anindication of the group within which the calling junctor lies is givento the control circuit. Ground from the middle right contact of relay622 extends over conductor 621, armature 692 of relay 599, conductor693, outer back contact of relay 539 to the winding of relay 529 andover the normal contacts of the lower numbered group test relays tobattery at the back contact of 'relay 529. Relay 529 closes a holdingcircuit to battery at its inner upper front contact. If junctors inother groups were calling, their relays might also operate, butpreference is given to the highest numbered group by reason of the chainwiring of relays 529 to 529. Assuming relay 529 operates, it extends itsoperating ground over its lower front contact, over the upper backcontact of relay 5H) to the winding of relay 54! and battery. Relay 529also closes a circuit from ground over its outer upper front contact,armature 594 of relay 699, winding of relay 629 to battery. Relay 629connects the individual group circuit serving the calling group ofjunctors to the control circuit.

Choosing y'unctor to be served Relay 529 in operating connects the tenstart leads such as conductor 42L from the ten junctors of the group,through to the ten trunk test relays 599 to 599, conductor 42! extendingover armature 528 of relay 629,.armature595 ofrelay 599, inner lowerback contact of relay 519 to the winding of relay 599 and battery. Itwill be noted that the start conductors of the ten trunks of the groupare connected together at the contacts of relay 625. Therefore theground from conductor 42! also extends over other back contacts of relay52! and front contacts of relays 629 and 999 to the windings of relay599 and the rest of the trunk test relays. Each relay locks to itsoperating ground, independent of relay 5l9. With all of the relays 599to 599 operated, a circuit is closed from battery through the winding ofrelay 52!, armature 629 of relay 529, armature 9960f relay 599, leftback contact of relay 549,

inner upper front contacts of relays 599 to 599, inner left contact ofrelay 54! to ground at the middle lower front contacts of all of therelays 599 to 599. Relay 62d in operating looks over its right frontcontact, conductor 64f, armature 642 of relay 629, armature 69'! ofrelay 599 to ground. It also disconnects the multiple ground from thetrunk relays and releases relay 622. Those relays, such as relay 599which correspond to calling trunks remain locked, but the remainingrelays release.

The release of relay 622 closes a circuit from battery through thewinding of relay 549, armature 698 of relay 599, armature 63l of relay629, back contact of relay 622, armature 632 of relay 629, armature 699of relay 699, outer lower front contact of relay 599 to ground over theoperating circuit of that relay. Relay 549 looks in a circuit frombattery through its winding, armature 698 of relay 599, armature 63! ofrelay 629, back contact of relay 622, armature 632 of relay 929,armature 699 of relay 699, to ground at the fifth right contact of relay549. With relay 549 operated, a circuit is closed at its fourth rightcontact for relay 539. Relay 539 opens the operating circuits of thegroup relays 529 to 529, leaving the highest numbered operated relay, inthis case relay 529, looked over the inner front contacts of relay 529,outer left contact of relay 54! to ground at the middle lower contactsof the operated trunk test relays. When relay 549 operates, it closes asubstitute holding circuit for relay 529 which may be traced frombattery over the inner upper front contact, winding and lower frontcontact of relay 529, middle left front contact of relay 549, armature 6ll of relay 699, arma-- ture 634 of relay 629, back contact of holdmagnet 425, conductor 426, outer back contact of relay E99, conductorE39, armature 533 of relay 629, armature 5l2 of relay 669, to ground atthe third right contact of relay 549. Parallel holding circuits extendover the other hold magnets and sender group relays serving the group.Therefore, if all links or all sender groups become busy, relay 529releases, in turn releasing the group relay 529 to normal so that othercalling junctors may be served.

Relay 549 also closes a locking circuit for the preferred trunk relay599 which extends over the inner and outer lower front contacts of relay599 to ground at the outer right front contact of relay 549. Thislocking circuit prefers the lowest numbered relay, the higher numberedrelays locking only over the back contacts of the lower numbered relays.However, if higher numbered relays were operated at this time, theywould remain locked to ground on the corresponding start lead.

Relay 599 also closes an obvious circuit for relay 5E9 which opens theoperating circuits of the trunk .test relays. Relay 5E9 also opens thethe primary sender selector.

' chain.

circuit of relay 54l which releases, but due to its slow-to-releasecharacteristic, only after an interval. Relays 536 and 5I6 in operatingprevent the operation of any further group and trunk relays shouldadditional calls be received.

Operating select magnet of primary sender selector Relay 5! also closesa circuit for the select magnet corresponding to the preferred junctorin This circuit may be traced from ground at the outer left back contactof relay 228, conductor 236, upper front contact of relay 5I6, outerupper front contact of relay 566, armature 6) of relay 666, winding ofprimary select magnet All) to battery, and in parallel to the selectmagnets of correspondingly positioned junctors in the other primaryswitches.

Test for idle sender group and link In the meantime the control circuithas been testing for a sender group and sender. Since this is a fullmechanical incoming junctor, group relay 626 connects ground over itsarmature 635 and armature 6I3 of relay 666 to conductor SM and thewinding of relay I26, which is individual to this junctor type andconnects the group test relays to the circuits controlled by fullmechanical senders only.

Assuming an arrangement similar to that shown in'Fig. 8, each group often senders includes eight full mechanical senders grouped in the tophorizontals of the switch and two B senders grouped in the bottom twocontacts of the switch. Each group of senders has a circuit such asshown in Fig. 7, relays H6 to H9 being individual busy relays for thesenders and relays I26 to I29 serving to test the condition set up onthe sender busy relays H6 to H9. Relays I68, I65 and 166 serve the fullmechanical senders, while relays I55, E58 and 'I3I serve the B senders.With relay I26 operated, the three sender groups are tested to determinewhether the link serving the calling trunk group is idle and'whetherthere are two or more full mechanical senders idle in the group. Onesender group test circuit may be traced from ground at the left backcontact of the link hold magnet 425, armature 636 of relay 626, armature6I5 of relay 660, conductor 6I6, outer right back contact of relay 22Iright winding of relay I66, right back contact of relay I21, outer leftfront contact of relay I26, conductor I3I,'armature 3I6 of relay 366,left back contacts of relays I62 and I65, outer left back contact ofrelay H6 to battery over the left normal contact of the next lowerunoperated relay in the chain. A similar circuit is closed over theouter back contact of each unoperated relay except relay II 1, whichbelongs to the last full mechanical sender of the group, to battery overthe inner left contact of the next unoperated relay in the Whereoperated relays intervene, the chain is extended to the following relay.This relay arrangement is disclosed and claimed in the application of A.J. Busch, Serial No. 68,240, filed March 11, 1936.

Circuits similar to the one traced for relay I 66 are closed for relaysI6! and I62 if the corresponding link and two full mechanical senders ofthe group are available. Assuming that relay I66 is operated, a circuitis closed from ground over the normal contacts of relays I63 and I64through the winding of relay I65, armature SI?! of relay, 366, outer,right front contact of relay I66, right back contact of relay I62, leftback contact of relay 2I8, conductor 232, inner left front contact ofrelay 546, conductor 555, right back contact of relay 228, resistance229 to battery.

seizing sender group Relay I65 is individual to the group of sendersrepresented by relay I66 in this link circuit. A similar relay (notshown) is provided for each of the other sender groups. Relays I63 andI64 belong to the same sender group as relay I65 but are a part of otherlink circuits. These relays are arranged in a lock-out chain in order toindividualize the sender group to a particular link circuit and toprevent interference from other link circuits. In this case the linkcircuit shown has the last preference for the sender group shown andrelay I65 can only operate if no other link control circuit isattempting to connect with this group of senders. Relay I65 whenoperated locks to ground at its own front contact and renders relays I63and I64 ineffective by disconnecting ground from their left armatures.With relay I65 operated, a locking circuit is closed for relay I66 whichmay be traced from battery through the left winding and over the innerleft front contact of relay I66, armature 3II of relay 366, outer leftfront contact of relay I65, to ground. This same ground is extended overthe inner left front contact of relay I65, armature 3I3 of relay 366, tothe winding of relay 22I and battery. A circuit is also closed fromground at the middle right contact of relay I65 to the winding of relayI62 and battery. Relay 22I opens the operating circuits of relays I66,MI and I62 causing relays ml and I62, for which no locking circuits havei been provided, to release.

Reserve sender group test When relay 54I closes its back contact, acircuit is closed from ground at the right back contact of relay 54 I,outer left front contact of relay 546, conductor 556, winding of relayI27 to battery. If none of the relays I66, IM or I62 has operated bythis time, relay I 27 transfers their circuits from the regular testover back contacts of the sender relays 'II6 to II I, to the reservetest to battery over the back contacts of relays I62 and I65 and thesimilar relays of the other sender group circuits. Relay 165 is operatedover the outer left front contacts of relays H6 to II! when all of thefull mechanical senders of the group are busy, thereby opening thecircuit of the corresponding sender group relay. Therefore for groupshaving a single idle sender, relay I65 will be unoperated and such agroup may be selected. The operation of relay 162 from relay I65, whenthe regular test is satisfied, cancels this reserve test, although relayI2! is operated.

Selection of idle sender With relays I66 and I65 operated and locked,the control circuit is ready to select an idle sender in the selectedgroup. A circuit is first closed from ground over the middle leftcontact of relay 22I, outer left front contact of relay I66, outer leftback contacts of relays I 6| and I62, middle left front contact of relayI66, armature 3M of relay 366, outer right contact of relay I65, windingof relay I56 to battery. Relay V56 connects the circuits of the selectedgroup of senders to the control circuit.

Relay I56 connects ground to conductors I8I,

182, E83 and 184. These conductors extend in multiple to the ten sendersof the group but are ineffective until a sender has been seized.Conductor l8! controls a relay which reverses the direction of currentflow over the contact of the stepping relay for calls received over partof the link circuits in order to save wear on the contact. Conductor F32supplies holding ground to the sender until after the off-normal relayhas operated. Conductors E83 and 584 carry the identity of the trunkgroup to the sender for transmission to the marker.

Operating select magnet of secondary sender selector Relay Hit alsocloses a circuit from battery through the winding of relay Hi8, armatureof relay 'l-ili, conductor 53%, armature 330 of relay 3%, to ground atthe outer right contact of relay i26. With relay lElB operated, thecircuits for selecting a sender are closed. Each trunk normally prefersa different sender but in this case, with only eight senders availablethe preference of two pairs of trunks would be the same. Thereforerelays 383 and W8 connect eight preference leads from the trunk relays5st] to 599 through the windings of the eight sender selecting relaysJ25 to Hi over contacts of the sender busy relays lid to ill. Sincetrunk relay 50!] was operated, the circuit closed at this time extendsfrom ground at the inner right front contact of relay 5%, middle upperfront contact of relay 5%, conductor 55?, armature 3H3 of relay 3%,conductor 3H, armature it? of relay 7150, inner right contact of relay768, right back contact of relay Hi1, assuming this sender to be idle,winding of relay was, left normal contacts of relays E21, 128, 129,etc., to battery. Relay 12o operates and locks to battery at its innerleft contact and to ground over its inner right contact and armature 132of relay 750. It connects ground over its outer right contact to thewinding of relay N32 to hold that relay operated. At its outer leftcontact it closes a circuit from ground over armature 188 of relay i159,conductor 1189 to the winding of the secondary select magnet notindividual to the selected sender. At the same contact it connectsground to conductor 5'92 to inform the sender that it has been selected.Relay 72% also connects ground over its middle right contact, armatureE98 of relay E59, conductor lsl, armature EH8 of relay Salli, to thewinding of relay 225 and battery.

When relay i552 operated, relay Ml was connected in parallel over thefour left back contacts of relay M6, the four outermost armatures ofrelay 3%, armatures F93 to 96 of relay 550 to conductors is? to E99 and75! leading in multiple to the group of senders to test them for thepresence of false ground. If any one of these conductors is groundedfalsely, relay ill operates, opening the circuit of relay H6 andblocking the progress of the call.

Operating linlc hold magnets If relay ill does not operate, theoperation of relay 225 closes a circuit from ground at its inner rightcontact over the back contact of relay i ii for relay 9 i 6 whichdisconnects relay i ll from conductors E9? to E99 and l'5i. With relayH6 operated, a circuit is closed for hold magnets 424 and, 525,belonging to the link circuit connecting the calling trunk and selectedsender, extending over the inner back contact ofrelay 523, armature $31!of relay 620, armature fill of relay Bill], conductor 6! 8, middlerightfront contact ofrelay I00, through the winding of relay ZIE shunted bythe outer left back contact of relay 2%, inner right front contact ofrelay I It, to ground at the inner right back contact of relay 224.Magnets 324 and 425 operate, closing the cross-points prepared by selectmagnets 400 and tilt. When magnet 424 closes its cross-point, theoperating ground for the magnets is extended over contact 445 of thesecondary selector, conductor 4%, to the sender.

Test of sender holding circuit When relay Z20 connects ground toconductor 192, it causes the operation of a sender relay which connectsconductor M6 to conductor 15i, armature 796 of relay l5fl, armature 3H5of relay 300, inner left front contact of relay i is, winding of relay220 and battery. Relay 22ft opens the shunt around the winding of relay2E5 and relay 2E5 operates, provided there is no false ground on thesleeve conductor of the sender link. Such a ground, while holding thehold magnets and relay 225 would be in shunt of the winding of relay2|5, preventing its operation and blocking the call.

Assuming relay 2H5 operated, it closes an obvious circuit for relay 214which looks under the control of relay 22H. Relay 2 it connects groundover its middle left contact, outermost contact of relay 3Ull,'armatureMS of relay l5), conductor EST, to the sender where it operates a relaywhich in turn connects ground to the winding of relay ill marking thissender busy to this and other link circuits.

Frame registration In the meantime, the incoming frame is identified tothe sender by ground connected to conductors 183 and 784 as previouslydescribed. In response to the completion of the frame registrationground is closed over conductor W9, armature of relay 150, armature 326of relay 3%, left back contact of relay 224, outer right contact ofrelay 2M, winding of release relay 228 and battery. This same ground isalso extended to conductor 446 to hold the magnets 424 and 325 operated,independent of the control circuit.

Release of control circuit Release relay 228 locks under the control ofrelays 223, I21, 22!, H6, 540 and 5M if operated, to insure that itremain operated until the control circuit has restored to normal. Italso connects ground over its left front contact, conductor 233,armature N9 of relay 6%, conductor 624, inner left back contact of relay5&3, winding of relay 5% and battery. Relayt lt locks to ground at'theright front contact of relay 552, opens the circuit'of relay 552 anddisconnects ground from conductor 558, thereby terminating the timingoperation. Relay 552 releases relay 5 2 which in turn releases relays 6%and disconnecting the sender and group circuits from the control.circuit. The release of relay 6% in turn releases group relay 629,select magnet ilt, relay 5:30, the group test relay 529 and trunk testrelay 566, as well as relays 5M and 533. 38s], in releasing, restoresthe link lock-out relay 555, sender group connect relay 15B, sender testrelay i283, sender select magnet and, relay H92 and relay 768, alsosender group test relay i953, and the remaining operated relays of Figs.'1 and 2, relay 228 releasing last.

Relay 62! releases following the release of relay .620 if no calls arewaiting in other groups. When Relay" calls are Waiting in other groups,the corresponding group start relay, for example relay 652, is operated,grounding conductor 64!, which is common to all groups, and therebyholding relay 62! operated and preventing the extension of a new call inthis group until other waiting groups have been served.

The junctor is now connected over the primary sender selector 438 andsecondary sender selector 440 to the terminating sender.

Emergency operation of control circuit Before proceeding to adescription of a call involving a B junctor, the operation of the linkcontrol circuit in connection with a mate frame will be described. Whenconductor 64! is grounded, this ground extends over the left backcontact of relay 545 to conductor 55% and an interrupter (not shown).After an interval the interrupter grounds conductor 559, operating relay553 which locks to conductor 558. After a further interval of about 6seconds the interrupter connects ground to conductor 56!), completing acircuit over the right contact of relay 553 to the winding of relay 541and battery. Relay 541 also looks to conductor 558, lights lamp 548, andoperates relay 543 over the left contact of key 544. Relay 543 opens theoperating circuits for relays 542 in both the home and mate controlcircuits and the circuit of relay 545 and transfers 7 the circuit ofrelay 546 from control by the sender relay and the release relay 228 tothe transfer relays 550 of the home and mate frames.

In addition, relay 543 closes a circuit for relay 550 which is effectiveif the transfer relay 555 and start relay 552 of the mate controlcircuit are idle. The circuit may be traced from battery through thewinding of relay 558, through rec'- tangle 350, over the outer left backcontact of the mate relay 550, right back contact of mate relay 552,back through rectangle 353, to ground at the inner right contact of homerelay 543. Relay 550 locks over its inner right contact to ground overkey 55! and therefore remains operated until released manually by theoperation of the key. Relay 553 further opens the circuit for mate relay542, operates relay 546, lights lamp 549, extends the start circuit fromthe front contact of relay 552 to the winding of mate relay 545, andopens the circuit of mate relay 550.

Relay 542, if operated, releases, in turn releasing relays 555 and 350.The operation, of relay 546 disconnects ground from conductor 558,releasing relays 553, 541 and 543. When relay 543 releases, mate relay545 operates, locking in- Timing for sender connection In the controlcircuit, relay 22! operates as soon as the control circuit is associatedwith a group of senders. Relay 221 at its inner right contact connectsinterrupter 222 to conductor 234, thereby grounding that conductor athalf second intervals. Relays 2H) and 2H function in the well-knownmanner, relay 2 operating at the beginning of the first pulse and relay2H] operating when ground is removed. Relay 2 releases at the beginningof the second pulse and relay 2I0 at the end, the cycle repeating aslong as the ground pulses continue. If the control circuit has notreleased when relays 2H and 2H] have operated and relay 2]! hasreleased, a circuit is closed from battery through the winding of relay2l8, outer right back contact of relay 224, inner left back contact ofrelay 220, right front contact of relay 2), left back contact of relay2! I, conductor 235, armature 623 of relay 600, conductor 625 to groundover the right contact of key 544. Relay 218 locks under the control ofrelease relay 223. Relay 2l8 opens the circuit of relay I05, releasingthe selected group of senders. Relay 2l8 also closes a circuit frombattery through the winding of relay 223, left front contact of relay2l8, left contact of relay 225, to ground at the right back contact ofrelay H5. Relay 223 also looks to the back contact of relay 228. Inselecting a sender group, the preference lead coming into the controlcircuit over conductor 232, normally extends over the back contact ofrelay 218 to the armature of relay I 02. With relays. 2I8 and 223operated this preference lead is extended over the front contact ofrelay 223 to the armature of relay IUD, thus endeavoring to seize adifierentsender group.

Relays 2H], 2H, 2l8 and 223 are. permitted to function if because offalse grounds relay H1 operates as previously described, or if becausethe cross-points fail to close properly, relay 220 does not operate. Ifrelay 220 operates, but because of double connections relay 2l5 does notoperate, when relay 2 falls back, the circuit above traced to relay 2! 8extends over the left front contact of relay 226 to the winding of relay224, which looks under the control of relay 22l. Relay 224 closes acircuit from battery through the winding of relay 423, conductor 439,armature 32l of relay 355, inner right front contact of relay I00,middle left front contact of relay 224, to ground at the left backcontact of relay 2l4. Relay 423 opens the circuits of hold magnets 424and 425 opening the corresponding cross-points and disconnecting groundfrom relay 220, which releases. It also connects ground over its leftcontact, conductor 438, armature 322 of relay 30B, outer right backcontact of relay 225, inner left front contact of relay 224, to thewinding of relay H9 and battery. Relay 2I9 operates and locks under thecontrol of relay 22L Relay 2l9 connects ground over its middle leftcontact, armature 323 of relay 35!], armature 194 of relay 150 toconductor 198 to release the sender. It also connects ground over itsinner left contact, outermost armature of relay 340, armature 193 ofrelay 155 to conductor 191, which ground is passed back over conductor15! and thence as previously traced to the winding of relay 220 andbattery. Relay 220 closes a circuit for relay 2l8 over the outer leftcontact of relay 2l9, inner right and left contacts of relay 220 to theright front contact of relay 2l0 and thence to ground as described abovewhen relays 2|!) and 2H reach the proper point in their cycle. Relay 2|8functions as previously described to release the sender group selectionrelays and to bring about a second trial.

If the sender is selected and otherwise operates correctly but fails tosend a release signal to the link Within the prescribed length of time,the functioning of relays 2H! and 2 will bring I group busy relays.

about the operation of relay 224 as described. If relays 226, 2I5 and 2Mhave been operated, when relay 2!!! releases after operating relay 224it closes ground over its back contact, outer left front contact ofrelay 224, outer right front contact of relay 2I4, winding of relay 228and battery. Relay 228 functions in the usual manner to release the linkcontrol circuit. If relays 226, 2I5 and 2I4 do not operate, the call istransferred to the mate control circuit.

Operation in connection with B iunctor When a call is originated on ajunctor to be served by a B operator, the group start conductor isgrounded in the same manner as by a full mechanical junctor. As abovementioned the B junctors are grouped together and will be served byindividual links. Assuming the B junctor indicated in Fig. 4 is seized,conductor 45! is grounded, operating the individual group relay 652. Thecircuit for relay 652 may be traced from grounded conductor 45!, backcontact of relay 65!, back contact of hold magnet 452, back contact ofrelay !3I, outer right back contact of relay 65!, contact of jack 65'!to the winding of relay 652 and battery. Parallel circuits are closedover the back contacts of the hold magnets of the other two linksserving this group of junctors and the corresponding sender Relay I3!operates from relay I55 which, in turn, operates over the front contactsof relays H8 and H9 if the two B senders of this group are both busy.

Relay 652 grounds conductor 64! to start the operation of the controlcircuit in the usual manner. Relay 542 is operated, in turn, operatingrelays 666 and 366. Relay 652 now indicates the identity of the callinggroup of junctors to the group relays 526 to 529 by closing a circuitfrom ground at its middle right contact, armature 653 of relay 666,inner lower back contact of relay 536 to the winding of relay 526 andbattery. Assuming'relay 526 is operated alone, it removes the operatingbattery from the higher numbered relays to prevent interference. It alsoextends its operating ground over its lower front contact and the backcontacts of thehigher numbered group relays including relay 529, upperback contact of relay 5!!) to the winding of relay 54! and battery.Relay 526 also closes a circuit from ground over the upper back contactsof relays 529 and the intermediate group relays, outer upper frontcontact of relay 526, armature 654 of relay 666, to the winding of relay655 and battery. Relay 655 performs the same functions for this group ofjunctors that relay 626 performed for its group. Since this B junctor isalso the first in its group, relay 655 connects start lead 45! overarmature 656 of relay 655, armature 665 of relay 666, inner lower backcontact of relay 5!!) to battery through the winding of relay 566.

All of the trunk relays operate and lock temporarily as above described.With relays 566 to 566 operated a circuit'is closed from battery throughthe winding of relay 65!, armature 658 of relay 655, armature 666 ofrelay 666, left back contact of relay 546, inner upper front contactsofirelays 566 to .569, inner left contact of relay 54! to ground at themiddle lower front contacts of relays 566 to 569. Relay 65! looks underthe control of relay 666 and opens the multiple ground allowing allrelays but relay 566 to release. Relay 65! also releases relay 652 whichcloses the circuit of relay 546 over armature 668 of relay 666, armature666 of relay 655,

left back contact of relay 652, armature 656 of relay 655, armature 669of relay 666, outer lower front contact of relay 566 to ground over theoperating circuit of that relay. Relay 546 supplies locking ground atits outer right contact in place of the ground supplied by relay 566.

Relay 566 operates relay 536, which in turn operates relay 5I6. Relay546 also provides a holding circuit for relay 526, which extends overthe lower front contact of relay 526 and the lower back contacts of theother group test relays, back contact of relay 529, middle left frontcontact of relay 546, armature 6! I of relay 666, armature 66! of relay655, back contact of magnet 452, back contact of relay I3I, armature 662of relay 655, armature 6I2 of relay 666 to ground at the third rightcontact of relay 546. As in the operating circuit of relay 652 there areparallel circuits over contacts of the hold magnets and sender groupbusy relays of other sender groups. In addition relay 546 also looksrelay 566 as before.

With relay 5 I 6 operated the select magnets corresponding to relay 566are operated as above described.

In the meantime the sender test is taking place.

ince this is a B junctor, group relay 655 connects ground over armature663, armature 664 of relay 666, conductor 665 to the winding of relayI32 and battery. With relay I32 operated the three sender groups aretested to determine whether the links are idle and B senders areavailable. The test circuit for the group shown extends from ground atthe left back contact of magnet 452, armature 666 of relay 655, armature6I5 of relay 666, conductor 6! 6, outer right back contact of relay 22!,right winding of relay I66, right back contact of relay IZ'I, outer leftcontact of relay I52, armature 33! of relay 366, conductor 332, outerright contact of relay I62, left back con,- tacts of relays E55, M8 andM9 to battery. This is under the assumption that the two B senders ofthe group to which relays H8 and H9 belong are idle. If one of thesenders were busy and the corresponding sender busy relay operated, thiscircuit could not be completed. If both senders were busy relay 655would be operated over the middle left front contacts of relays H8 andH9, in turn, operating relay 13 I.

Similar test circuits are closed for relays I6! and I62. With at leastone sender busy in each group, the regular test would fail and thereserve test he made under the control of relay !2!. The reserve testcircuit for relay I 66 extends over the outer right front ccntact ofrelay I21, inner right contact of relay I32, armature 333 of relay 366,conductor 334, inner right back contact of relay 762, to battery at theright back contact of relay I55. If both senders are busy so that bothtests fail, this group of senders cannot be used.

Assuming, however, that the reserve test is successful, relay H8 beingoperated but relay H9 idle, relay I66 will operate, in turn, operatingrelay I65, which provides a locking circuit for relay I66, and anoperating circuit for relay 22!. Relay I65 also operates relay I62.

With relays I66 and I65 operated, relay I56 is operated as previouslydescribed. Relay I56 closes a circuit from battery through the windingof relay T58, armature 765 of relay I56, conductor I86, armature 3I5 ofrelay 366, outer right contact of relay I32 to ground. Relay I58 closesa sender selecting circuit from ground at the inner right front contactof relay 546, middle upper front contact of relay 566, conductor 55!,armature 3I6 of relay 666, conductor 3II, armature 18! of relay ldttinner right contact of relay 158 to the outer right armature of relay 7l 8. Since it was assumed that relay H8 is operated, the circuit extendsover the outer right front contact of relay H8, right back contact ofrelay H9, winding of relay i228 and battery.

Relay i233 locks to ground on armature 732 of relay 75d, and connectsground to the winding of relay m2. It also closes a circuit from groundover the left back contacts of relays 120 to 128, outer left frontcontact of relay 129, armature E3? of relay 75B, conductor F38, windingof sender select magnet W9 and battery. A branch of this circuit extendsover conductor 142 to the sender.

At its middle right contact relay 12!! connects ground to the circuit ofrelay 225, which operates relay lit as previously described. With relayH6 operated, a circuit is closed from ground at the inner right backcontact of relay 224, inner right front contact of relay I I6, throughthe winding of relay 2E5 shunted by the outer left back contact of relay220, middle right front contact of relay lilii, conductor 6H3, armature6|! of relay 6B0, armature 651 of relay 655, outer right back contact ofrelay 423 to the windings of hold magnets 4 ,52 and 45 5. These magnetsclose the crosspoints prepared by select magnets 453 and 409, completingthe connection between the junctor and sender.

The testing of this connection and the release of the control circuittake place in the same manner as for a full mechanical junctor.

What is claimed is:

1. In a telephone system, a terminating oifice, trunk circuits incomingto said ofiice from manual ofiices, registering devices for associationwith said manual trunk circuits, trunk circuits incoming to said officefrom dial oilices, registering devices for association with said dialtrunk circuits, and a unitary switching device for connecting any one ofsaid trunk circuits with one of the corresponding registering devices.

2. In a telephone system, a terminating ofl1ce, trunk circuits incomingto saidofiice from manual ofiices, registering devices for associationwith said manual trunk circuits, trunk circuits incoming to said ofiicefrom dial oilices, registering devices for association with said dialtrunk circuits, and a unitary switching device responsive to seizure byany one of said trunk circuits to connect said trunk circuit with one ofthe corresponding registering devices.

3. In a telephone system, a terminating oflice, trunk circuits incomingto said ofiice from manual offices, registering devices for associationwith said manual trunk circuits, trunk circuits incoming to said officefrom dial ofiices, registering devices for association with said dialtrunk circuits, a unitary switching device, means for seizing saidswitching device by any one of said trunk circuits, means associatedwith said switching device to record the type of said trunk circuit,means for testing said registering devices, and means under the controlof said recording means to cause said testing means to test only thoseregistering devices corresponding to said trunk circuit.

4. In a telephone system, a terminating ofiice, trunk circuits incomingto said office from man-. ual oifices, trunk circuits incoming to saidoifice from dial oifices, first registering devices for association withsaid manual trunk circuits, other registering devices for associationwith said dial trunk circuits, said registering devices being arrangedin groups containing both said first registering devices and said otherregistering devices,

a unitary switching device, means for seizing said switching device byany one of said trunk circuits, means associated with said switchingdevice to record the type of said seizing trunk circuit, a testingcircuit associated with said switching device for testing each of theregistering devices of a group, and means under the control of saidrecording means for rendering only those testing circuits efiectivewhich test registering devices associable with the seizing trunk.

5. In a telephone system, a terminating ofilce, trunk circuits incomingto said office from anual oflices, trunk circuits incoming to said oihcefrom dial oflices, first registering devices for association with saidmanual trunk circuits, other registering devices for association withsaid dial trunk circuits, said registering devices being arranged ingroups containing both said first registering devices and said otherregistering devices, a unitary switching device, means for seizing saidswitching device by any one of said trunk circuits, means associatedwith said switching device to record the type of said seizing trunkcircuit, means for testing said registering devices comprising a set ofrelays one for each registering device in the group, and means under thecontrol of said recording means for rendering only those relayseifective which test registering devices associable with the seizingtrunk.

6. In a telephone system, a terminating ofiice, trunk circuits incomingto said ofiice from manual offices, trunk circuits incoming to saidoffice from dial offices, first registering devices for association withsaid manual trunk circuits, other registering devices for associationwith said dial trunk circuits, said registering devices being arrangedin groups containing both said first registering devices and said otherregistering devices, a unitary switching device, means for seizing saidswitching device by any one of said trunk circuits, means associatedwith said switching device to record the type of said seizing trunkcircuit, means for testing said registering devices comprising a set ofrelays one for each registering device in a group, and means foroperating one of said relays under the joint control of said recordingmeans and the registering devices under test.

7. In a telephone system, a terminating ofifice, trunk circuits incomingto said ofiice from manual o-fiices, trunk circuits incoming to saidoffice from dial oilices, first registering devices for association withsaid manual trunk circuits, other registering devices for associationwith said dial trunk circuits, said registering devices being arrangedin groups containing both said first registering devices and said otherregistering devices, a unitary switching device, means for seizing saidswitching device by any one of said trunk circuits, means associatedwith said switching device to record the type of said seizing trunkcircuit, means for testing said registering devices comprising a set ofrelays one for each registering device in a group, and means foroperating a particular one of said relays under the joint control ofsaid seizing trunk, said recording means and the registering deviceunder test.

8. In a telephone system, a terminating oifice, trunk circuits incomingto said oflice from manual offices, registering devices for associationwith said manual trunk circuits, trunk circuits incoming to said ofiicefrom dial omces, registering devices for association with said dialtrunk circuits, a unitary switching device, comprising primary andsecondary cross-bar switches and links interconnecting them, sets ofcontacts in said primary switches and links individual to each type oftrunk, sets of contacts in said secondary switches individual to eachtype of registering device and accessible to both types of link, andmeans for preventing links of one type from engaging contacts belongingto registering devices of the other type.

9. In a telephone system, a terminating ofiice, trunk circuits incomingto said office from manual ofiices, registering devices for associationwith said manual trunk circuits, trunk circuits incoming to said ofiicefrom dial offices, registering devices for association with said dialtrunk circuits, a unitary switching device, comprising primary andsecondary cross-bar switches and links interconnecting them, sets ofcontacts in said primary switches and links individual to each type oftrunk, sets of contacts in said secondary switches individual to eachtype of registering device and accessible to both types of link, andmeans for permitting links of one type to engage only contacts belongingto registering devices of the same type comprising means for recordingthe type of an incoming trunk, means under the control of said recordingmeans for testing only the corresponding type of registering device, andmeans under the control of said testing means to prepare a set ofsecondary switch contacts.

10. In a telephone system, a terminating ofiice, trunk circuits incomingto said ofiice from manual ofiices, registering devices for associationwith said manual trunk circuits, trunk circuits incoming to said ofiicefrom dial offices, registering devices for association with said dialtrunk circuits, a unitary switching device, comprising primary andsecondary cross-bar switches and links interconnecting them, sets ofcontacts in said primary switches and links individual to each type oftrunk, sets of contacts in said secondary switches individual to eachtype of registering device and accessible to both types of link, andmeans for permitting links of one type to engage only contacts belongingto registering devices of the same type comprising means for recordingthe type of an incoming trunk, a set of relays for testing each group ofregistering devices, means under control of said recording means forpreparing the circuits of those test relays only which test thecorresponding type of registering device and means under the control ofsaid test relays to prepare a set of secondary switch contactsindividual to a registering device of corresponding ype.

WARREN W. CARPENTER. ALFRED E. HAGUE.

